Food. And warmth.

Two vital elements for surviving winter. Always have been, and always will. The buzzwords for this post which attempts to draw together at least four special sightings here over the last ten days.

Let’s begin with the last cold snap. Several days with nights down to minus 8 degrees C, and days not even creeping above freezing. Nipping out after dark, to use the pee can behind the back door, I timed it to perfection. A ghostly, pale owl shape flew silently past, barely 10 yards from me and just above the veg beds. But perhaps startled both by me, and switching on the outside light, it let out a short screech. Was it a Barn Owl? Fiona quickly did a search, and the online call of a barn owl was a precise match.

In all our 30 years here, we’ve never seen or heard one before. How exciting. Questions followed. Was it a local bird? Might it use our main barn, if a suitable opening was made, and a nest box built? Could it co-exist with swallows in the same space? Some hints are given in this excellent short piece from the Barn Owl Trust. It really does seem that food supply is the key criterion.

2 days later we checked the forecast before nipping out for a meal at the excellent Cawdor Arms Hotel in Llandeilo. No sign of any snow in the forecast, so we figured the gritted roads would be fine. They were, but light hail flurries began as we returned, and as we neared Talley, we saw another Barn Owl flying over the fields to the South. We wondered if they were struggling to find food in the frozen landscape, and having to extend their feeding range. There are two excellent reviews of the diet and habitat necessary to support Barn Owls here.  And here. But finding the necessary 3 or 4 small mammals daily – like field voles, shrews or wood mice – must be challenging in such very cold weather. The owls prefer to have rough open grazing over which to fly, which provides ample cover for such small prey. In our local landscape, there are now far more fields like this as many landowners have reduced stocking densities.

No chance of me ever filming one, I guess, but this YouTube, from BBC EARTH with some clever artificial setups with a trained bird shows you how they manage to hunt so successfully.

The following morning, our Tesco delivery van couldn’t make it up our hill. The small amount of fine hail on the frozen surface played havoc with the van’s automated transmission. So we togged up and took the wheelbarrow down to unload our groceries, and watched as the poor driver had to slowly reverse down the track to a more open point where he could access the food trays. Fiona noticed the van’s rear wheels weren’t turning, and it turned out that the snazzy electronic hand brake had locked the wheels. Fortunately, a few on and off with the ignition and the problem was resolved, at least temporarily. No risk of our food supplies running out – we always anticipate such dramas in the winter, and keep big stocks in. However, it highlighted our lack of real resilience as a species in modern times, with so many complex systems we all rely on working efficiently.

At least for keeping warm we now have a wonderfully warm, cork-insulated home, and a wood-burning stove, to complement our wood pellet boiler. In really cold snaps it still requires around 30 KG of wood, as logs or pellets, to keep the temperature around our comfortable minimum of about 17.5 degrees C. We’ve always valued the wood burner, in part because we can use our own onsite fuel. In part because of its simplicity and resilience. If, as happens occasionally, the power goes, we can keep warm, boil a kettle and cook. But what happens in the wider world in the current push towards an electric-only life? For transport, and heating. Power outages, for whatever reason suddenly become a BIG problem in cold weather, but this rarely seems to be discussed. Heat pumps may be very efficient, but as with any central heating, lose your power, and you’ve lost your heat. What’s Plan B?

I’d just read Manon Steff Ros’s (adapted from the Welsh original) thought provoking Blue Book of Nebo. And been struck in this tale of mother and young son surviving ‘The End’, that it was the loss of all power that was a defining feature of their new adaptive life in a world largely devoid of other people.

As for relying on increasing numbers of ever larger wind turbines to generate much of the UK’s electricity, check out this issue with toxic fallout from abrading wind turbine blades, which only came across my radar recently. Lest you think this is a hyped-up scare story, perhaps you could watch ‘Dark Waters’, as we did this month. One does worry about just how many toxic, or ‘forever’ chemicals are entering the environment around us, with little hope that they can ever be removed. Our water engineer son confirms this – anything that’s currently removed from sewage treatment plants as sludge gets put back onto fields as fertiliser. Just what else can you do with it? From where, of course, it eventually finds its way into groundwater, runoff, rivers and the sea. Hmmmm.

Food AND warmth are critical over the winter months, for any animal.

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It’s always a time of year when I get excited by the daily opening of increasing numbers of late winter flowers, and even more so by seeing signs of life from the honey bee colonies we host around the property – all housed in cork-insulated simple structures. On any suitable day, typically between about 11.30 am and 3.00 pm, I’ll make a quick check of flowers and hives to see if there are signs of activity. This year we went into winter with 4 out of 6 available boxes, with active colonies. But this January has, to date, only had 3 days with potentially suitable foraging conditions. Perceived temperature, wind, and just as importantly direct sunlight are critical in allowing the bees to fly out, and return safely.

4 days ago we had the best conditions so far this year, with sunshine and relatively light winds, so that although the perceived temperature was only about 5.5 degrees C, all the snowdrop flowers began to open their outer segments, as did the first Crocus. It’s amazing how quickly scouts inside a well-insulated box will detect this change in external conditions, and once a few intrepid workers have ventured forth and returned, the message gets around. So I seized the moment and got into the garden to record all this, and was amazed to see for the first time, an overwintered bumblebee queen joining in with the honey bees and venturing forth. This is a good 2 weeks earlier than I’ve ever witnessed before, up here. Not only that, but it was systematically visiting snowdrop flowers. Something I’ve very rarely seen in all my years of studying snowdrop and bee interactions.

As the wind picked up, it was clear that the honey bees stayed much longer inside individual flowers, often hanging on by a single talon, while they groomed and collected the pollen grains. And in the brisk winds, probably still being a bit shaky after weeks cooped up, several lost their grip and fell vertically from the flowers. Quite a contrast with the bigger, hairier, bumblebee which had more of a smash-and-grab approach, speedily flitting from flower to flower.

One of the other things I always check for around now is whether any of the bees are taking pollen into the hive – always a sure sign that the queen bee is beginning to start laying eggs again, after a winter pause. The bees will need plenty of pollen as a food source to feed the young bee larvae which hatch from their eggs after just a few days. Although I could see a few bees actively collecting snowdrop pollen in the garden, which hives were they coming from? Always difficult to spot with the naked eye, when bees can be flying in at great speed. Pausing video clips helps a great deal in this regard. However, by January 28th, at least 2 of the colonies were taking pollen inside. This is about a week earlier than I’d noticed last year.

I’d wandered up to check activity from the (usually) most vigorous colony behind the hay shed and was standing well wrapped up in a very gusty cold wind when there was a blur of movement from the base of the fence between me and the hive. In an instant, a male sparrowhawk flew up, perched on the fence post to the left of this photo, and just sat there. Needless to say, I hadn’t taken my camera with me. And perhaps that’s just as well since swinging the lens up would probably have startled it. As it was, I stood, fixed and fixated, barely 3 metres from this beautiful bird, which seemed to completely ignore me in my tatty thick green pullover and brown beanie.

It behaved as the perfect criminal. On edge, hyper-alert. Yellow, piercing bright-eye glancing, quickly, this way and that. Scanning its familiar territory. Its marvellous flecked breast framed with russet chest feathers. Enough time, as with my close encounter with a squirrel, twelve years ago, for me to contemplate how this scene was going to end. And wonder, if only…

Then in the most agile duck and dive, it dropped from the post, dipped into a right-angle dive and flew West, then banked behind the yews and turned to follow the hedge line, South. Confirmation, if needed, of the likely culprit for the crime scene of the poor Robin’s demise, which I featured last time.

It was only on the walk back inside that I realised that I hadn’t seen any dunnocks as I’d walked across the yard and up to the croquet lawn.

Ever since the big oak had dropped its mast crop of acorns, last autumn, 2 or 3 dunnocks have been ever-present low-level companions, in this part of the garden. Completely unfazed by my presence, they’ve taken over from robins this year. My guess is that the sparrowhawk had already struck that morning, and the small birds were all hunkered down in the safety of thickets or hedges.

Thinking that would be the end of sparrowhawk dramas for a while, Fiona and I were startled by a kerfuffle from the hawthorn at the edge of the terrace garden as we sat outside with a coffee a few days later. At first, we thought it was amorous house sparrows. Then realised that it sounded like a more physical bash of a bird’s wings or feathers. As Fiona commented to me that she’d just seen a large bird fly into the tree, and the sparrows had then followed it, I grabbed the camera from the table, swung it up, in time to catch the hawk dip out from the far side of the bush and down and away across the valley.

By now I was reflecting on how much more of this activity seems to take place around us, as the garden and landscape have changed over the years we’ve been here. It’s not simply that we’re more attuned to it.

Our upper pond, which was dug out for us by Ron Hughes probably 25 years ago, has gradually silted up but always provides a haven for damsel and dragonfly larvae and adults over the summer, and the main site for our frogs to spawn in the late winter. Usually, we see the first spawn in early February, but I’d noticed that our regular visiting heron, was beginning to spend time in the pond, rather than on the stream bank, despite the approach of another full moon.

It’s an incredibly wary bird. Even looking down on the pond from the terrace garden, nearly 100 yards away, if it glimpses your movement, it’ll fly off. Some mornings as I was feeding the sheep, or finishing laying the hedges it seemed to wait a bit longer before taking to the air. Perhaps the frogs were already beginning to become active? I wandered over but could see nothing at all in the Marestail and bogbean-clogged water. Not even a stickleback moving. But the heron soon returned, so I crawled beneath the holly back up at the house, and with maximum camera zoom tried to get some photos and video. I quickly realised that even well wrapped up, I was no match for the heron in either patience or in the ability to avoid hypothermia.

It just sat there, largely immobile except for some wind ruffled feathers. I just squatted there, with my flexed knee getting more achy. After a while, something seemed to catch its attention. Its whole posture changed, it extended its neck and beak and carefully moved closer to whatever had caught its beady eye. It was then I was able to notice a whole sequence of first neck, and then whole body swaying. I expected a strike to follow. But nothing happened, it reverted to sitting, head drawn in and eventually, both the camera battery and my chilling body gave up. The heron was still there, ever watchful. Ever patient.

It didn’t return for a couple of days, and then as I was finishing the very last section of hedge, after disturbing it from the pond as I’d walked down the hill to start, I noticed it fly past once more. It was clearly very keen to get back into this pond. By now I’d worked out that another holly tree lower down the hedgerow of Cae Efail would allow me a much closer filming point, with a hidden approach walk from the heron’s view as it stood amongst the bleached bankside Purple Moor Grass seed stems surrounding the shallow water.

I arrived in the nick of time, and as I carefully tried to get a view through the holly, I noticed it had already caught a frog.

Maybe it was its’ first of the season since it took it a long time to actually swallow the poor frog. The other interesting behaviour is how it repeatedly dunked, then shook the frog – perhaps 20 to 30 times, before attempting to swallow it. And then how it had a gulp or two of water for good measure. I’m sure this is some sort of cleaning behaviour, but could find no specific confirmation. Many species of frog produce bufotoxins from glands in their skin, which may be unpleasant for a predator. Globally, in some species of frog they are highly toxic, but there seems to be no detail on any such noxious substances released by this, our native common frog, Rana temporaria.

Within a minute or two of completing the swallowing, it was alert and on the hunt for another frog. This time I managed to film the actual moment of strike, and there followed the same multiple dunking and shaking before it slipped down to join its fellow.

Pleased with my efforts and again getting a little uncomfortable after 20 minutes crouching amongst damp oak leaves, I called it a day, around 12 pm. Not so the heron. It stayed there until the dusk light became so poor I had to give up. Herons can feed at night, and take multiple frogs in a day. But by now my brain was whirring. The most obvious question was how these extremely patient birds could survive the extreme cold of standing often motionless, with their feet in water for such long periods?

Three interesting facts about heron anatomy and physiology were eventually tracked down.

Firstly, there’s very little soft tissue in the lower part of the heron’s leg and foot – the part that stays immersed in the water. The skin of the foot is more scale-like, almost reptilian, and apart from that it’s just sinews, bone and blood vessels. The muscles controlling the feet are higher up, and well insulated with feathers.

Next, the heron, in common with many waders, has a very clever countercurrent heat exchange mechanism towards the base of the feathered part of its leg. This involves a network of fine branching small arteries, called the rete tibiotarsale,(45 in the picture below), which wraps around the veins returning cold blood from the foot. We have nothing like this in our legs.

These images are from a dissection study of a goose’s vasculature, which is similar to a heron’s.

This complex blood vessel network ensures that much of the heat from the body is used to warm the very cold venous blood returning from the foot, and hence the whole body core temperature isn’t too badly diminished after all that time spent with otherwise cold blood returning from the feet. It’s also hinted in some papers that some of the arteries in the distal part of the leg have valves within them which can reduce blood flow to the peripheral foot in such conditions. No doubt temperature and pain receptors in the distal nervous system are also set up in such a way as to be more tolerant of such conditions than in our own fingers and toes.

Finally, what about body temperature generally, being so inactive for long periods in cold winds, above cold water? Here one needs to think about the peculiar features of the heron’s gut. Whereas many birds have a layout similar the that above, with a crop in the lower neck to store food, which is then gradually released into a powerful grinding zone called the gizzard, (the striped feature to the right of the liver, above). Which is often filled with grit to aid in grinding up grain: the heron has neither of these.

Rather a very long oesophagus ends in a sac-like stomach, which caught prey can move into, for slow processing. In this wonderful line drawing of a dead grey heron’s digestive tract, drawn in 1974 by a comparative anatomist working at Cambridge, the stomach contents of 5 fish, in varying stages of digestion are shown to scale. I vaguely remembered that there’s an inherent heat benefit associated with eating. What used to be known as the heat increment of feeding. It’s now called, rather less helpfully, specific dynamic action.

(This paper,  “Going to sleep with a full belly: Thermal substitution by specific dynamic action in shorebirds”. This summary, “Specific dynamic action: A century of investigation”, discusses the increased metabolic activity postprandially in animals).

The net effect is that all the enzymic release, digestive processes and other muscle movements associated with consuming a meal of live frogs will probably help considerably with keeping the heron warm, as it stands motionless, waiting for the next prey to give itself away. And after a really successful fishing trip, the heron can probably sleep it all off for a long while. (It didn’t return the day after its mammoth frog-hunting trip or the following day.)

I’ll finish this discussion with a personal observation.

Or even advice, as someone who’s been a lifelong rapid eater, and gulper of food. Probably inevitable as one of 4 brothers, who then moved into 24-hour veterinary cover, where one never knew when the next phone call or emergency would appear. Remember that we too have molars.

Chewing, and grinding teeth. I’d been thinking about this in the light of my changed, post-COVID era diet, and significantly influenced by all the good work being done by the group of scientists and big data crunchers at Zoe. But then I watched, and heard, one of our ewes come over to a section of very thorny hawthorn which I was dealing with in the hedge. The surplus brash gets chucked into the fields and the ewes are selectively onto anything valuable, in a flash, especially hazel catkins and willow bark. But on this occasion, a single ewe grabbed the hawthorn stem, complete with fearsome thorns, and nipped off all the berries. There was then the most wonderful, lengthy grinding sound as it worked the berries to a pulp, before swallowing them. As vets, we all studied the physiology of the ruminant’s grinding of poor quality herbage to allow the complex four-stomach’s bacteria and fungi to get to work on processing it for optimal nutrient absorption. Not just once, but twice, after regurgitation and yet more grinding of molars. And also horses’ and rabbits’ different ways of tackling the same problem of how to use microbes to process the otherwise indigestible.

It’s only much more recently that we’re coming to realise just how important similar processes are for our own well-being. Rather like the horse and rabbit: it’s just that this mainly happens lower down in our digestive tract, where our colon-based microbiome does its unseen and vital work.

If you’ve never thought about this, the latest Zoe podcast covers some interesting ground. (I should add as a disclosure that I’ll never cough up for the ZOE programme, I don’t think. But I have been helped greatly by lots of their discoveries and freely available ideas, in their excellent podcasts. I’ve also sunk a small amount into the company through crowdfunding to try to support them in their journey. Not because I have any anticipation of ever seeing a financial return, but rather because I’d love them to gain some traction in the general mindset and approach to food and eating in the UK. They’re still massively unprofitable).

I can’t help but think that our dear Prime Minister would do better to spend a little of the vast, and evidently ever-increasing sums of our money poured into the bottomless stomach of our National Health Service (NHS), on such nutritional advice and support.

(Quite how we came to receive the above personalised letter and questionnaire from Rishi recently, requesting our views, and making some rather banal comments, I don’t know. Perhaps it was AI bot generated?)

After all, it seems that on both targets for treatments or procedures, let alone the growing evidence of falling life expectancy in the last couple of years, our current NHS system doesn’t appear to be achieving highly. As far as the health of the nation is concerned.

Which is, by definition, how it should be judged. Isn’t it?

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Finally a restful piece of music, “As I Was”, from Olivia Belli’s recent album Sol Novo. Played on her stripped-back, open upright piano, and recorded at her home in Covid times, I guess. A simple, soft percussive sound. It’s wonderful for sitting down and listening to. Quietly. A gentle contemporary revelation, for these late winter days.